福建永定大坪花岗斑岩体的铌钽富集特征研究  

Enrichment characteristics of Nb and Ta of Daping granite porphyry in Yongding,Fujian Province

作　　者：刘永超[1] 李建康[1] 邹天人[1] 江善元[2] 胡明月[3] 陈振宇[1] LIU YongChao LI JianKang ZOU TianRena JIANG ShanYuan HU MingYue CHEN ZhenYu(Institute of Mineral Resources, Chinese Academy of Geolc~ical Sciences, Beijing 100037, China No. 2 Geoexploration Institute of CEEB, Putian 351111, Fujian, China National Research Center for Geoanalysis, Beijing 100037, China)

机构地区：[1]中国地质科学院矿产资源研究所,北京100037 [2]中国冶金地质总局第二地质勘察院,福建莆田351111 [3]国家地质实验测试中心,北京100037

出　　处：《矿床地质》2017年第1期143-157,共15页Mineral Deposits

基　　金：国家重点研发项目(编号:2016YFC0600204);国家自然科学基金项目(编号:41372088);中央级公益性科研院所基本科研业务费专项基金(编号:K1409);中国地质调查局地质调查项目(编号:DD20160056;DD20160055)联合资助

摘　　要：福建大坪花岗斑岩体位于永定县城南部的大石凹—蓝地火山喷发盆地,具斑状结构,基质呈霏细结构、细-微粒结构。文章运用电子探针(EMPA)和激光剥蚀电感耦合等离子体质谱仪(LA-ICP-MS)等技术,对大坪岩体ZK10001钻孔中不同深度的岩石样品进行了矿物和岩石化学分析。分析结果表明,大坪岩体岩性为黑鳞云母碱长花岗斑岩,属于过铝质钙碱性花岗岩,具有较高的分异演化程度,Nb2O5和Ta2O5含量达到了花岗岩型稀有金属矿床的工业品位。铌钽矿物主要与黄玉、萤石的集合体呈稀疏浸染状、星点状产于基质间隙内,其次以星点状存在于石英和长石斑晶中。矿石矿物赋存特征与宜春钽铌矿床类似,可能具有一定的可选性和经济价值。大坪岩体的铌钽富集特征不同于斑岩型铜、钼矿床,与花岗岩型铌钽矿床也存在较大的差别,铌钽的富集过程经历了深部斑晶阶段和浅部基质阶段两阶段岩浆结晶分异作用,F等挥发分促进了铌钽在结晶残余岩浆中富集,在基质间隙间沉淀。大坪矿化岩体的发现暗示斑岩型铌钽矿床存在的可能性。The Daping granite porphyry intrusion with Nb-Ta mineralization is located in Dashiao-Landi volcanic basin in the south of Yongding,Fujian Province.The intrusion is characterized by porphyritic texture,felsitic texture and micro-fine granular texture in the matrix.The mineralogical and petrochemical characteristics of the rock samples from different depths of drill hole ZK10001 were investigated by means of electron microprobe analysis and laser ablation inductively coupled plasma mass spectrometry.The result indicates that the rock is protolithionite alkali-feldspar granite porphyry and belongs to peraluminous calc-alkaline series with a high degree of evolution,whose Nb_2O_5 and Ta_2O_5 values reach industrial grades of granitic Nb-Ta deposit.The ores mainly exhibit disseminated and fine-grained disseminated structure,in which ore minerals mostly occur in voids of matrix as mineral aggregates of topaz,fluorite and niobium-tantalum minerals,while a fraction occurs in phenocrysts.The occurrence characteristics of ore minerals are similar to those of the Yichun Ta-Nb deposit,which may meet the demand of ore dressing and smelting and may have certain economic value.The enrichment characteristics of Nb and Ta of Daping intrusion indicate that the enrichment process can be divided into two stages： Phenocrysts formation in deep process and matrix formation in shadow process,which is different from features of porphyry Cu-Mo deposits and granitic Nb-Ta deposits.Nb and Ta tended to enter residual melt and were concentrated in voids of the matrix under the role of volatiles（ for example,F）.The mineralization characteristics of Daping intrusion imply the possible existence of porphyry Nb-Ta deposit.

关 键 词：地质学 矿物学 岩石化学 花岗斑岩 铌钽 福建永定 

分 类 号：P618.79[天文地球—矿床学]